silent-inputs.html

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This test has a WPT meta file that expects 7 subtest issues.
This WPT test may be referenced by the following Test IDs:
- /webaudio/the-audio-api/the-waveshapernode-interface/silent-inputs.html - WPT Dashboard Interop Dashboard

<!doctype html>

<html>

  <head>

    <title>

      Test Silent Inputs to WaveShaperNode

    </title>

    <script src="/resources/testharness.js"></script>

    <script src="/resources/testharnessreport.js"></script>

    <script src="/webaudio/resources/audit-util.js"></script>

    <script src="/webaudio/resources/audit.js"></script>

  </head>

  <body>

    <script id="layout-test-code">

      let audit = Audit.createTaskRunner();

      let sampleRate = 16000;

      // Identity curve for the wave shaper: the input value is mapped directly

      // to the output value.

      let identityCurve = [-1, 0, 1];

      let nonZeroCurve = [0.5, 0.5, 0.5];

      audit.define(

            label: 'test-0',

            description: 'curve output is non-zero for silent inputs'

},

          (task, should) => {

            let {context, source, shaper} =

                setupGraph(nonZeroCurve, sampleRate, sampleRate);

            source.offset.setValueAtTime(0, 0);

            context.startRendering()

                .then(audioBuffer => {

                  should(

                      audioBuffer.getChannelData(0),

                      'WaveShaper with silent inputs and curve ' +

                          JSON.stringify(shaper.curve))

                      .beConstantValueOf(0.5);

})

                .then(() => task.done());

});

      audit.define(

            label: 'test-1',

            description: '2x curve output is non-zero for silent inputs'

},

          (task, should) => {

            let {context, source, shaper} =

                setupGraph(nonZeroCurve, sampleRate, sampleRate);

            source.offset.setValueAtTime(0, 0);

            shaper.overSample = '2x';

            context.startRendering()

                .then(audioBuffer => {

                  should(

                      audioBuffer.getChannelData(0),

                      'WaveShaper with ' + shaper.overSample +

                          ' oversample, silent inputs, and curve ' +

                          JSON.stringify(shaper.curve))

                      .beConstantValueOf(0.5);

})

                .then(() => task.done());

});

      audit.define(

            label: 'test-2',

            description: 'curve output is non-zero for no inputs'

},

          (task, should) => {

            let {context, source, shaper} =

                setupGraph(nonZeroCurve, sampleRate, sampleRate);

            source.disconnect();

            context.startRendering()

                .then(audioBuffer => {

                  should(

                      audioBuffer.getChannelData(0),

                      'WaveShaper with no inputs and curve ' +

                          JSON.stringify(shaper.curve))

                      .beConstantValueOf(0.5);

})

                .then(() => task.done());

});

      function setupGraph(curve, testFrames, sampleRate) {

        let context = new OfflineAudioContext(1, testFrames, sampleRate);

        let source = new ConstantSourceNode(context);

        let shaper = new WaveShaperNode(context, {curve: curve});

        source.connect(shaper).connect(context.destination);

        return {context: context, source: source, shaper: shaper};

      audit.run();

    </script>

  </body>

</html>